GMC Forward Control P3500 (1985-1999) speed meter Wiring diagrams

18 19 PNK WIRE A/C COMPRESSOR CLUTCH RELAY (RIGHT SIDE OF DRIVER'S ISLAND) A/C HIGH PRESSURE CUT-OFF SWITCH (ON REAR OF THE A/C COMPRESSOR) BLK WIRE BLU WIRE BRN WIRE BRN/WHT WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECM B FUSE 6 ENG BAT FUSE 10 FUEL LIFT PUMP (INSIDE RIGHT FRAME RAIL, AHEAD OF FUEL TANK) FUEL PUMP PRIME CONNECTOR FUEL PUMP RELAY (IN UNDERHOOD FUSE/RELAY CENTER) FUEL PUMP SWITCH AND ENGINE OIL PRESSURE GAUGE SWITCH (LEFT REAR OF ENGINE) GAUGES FUSE 8 GRN WIRE GRY WIRE HOT AT ALL TIMES HOT IN RUN AND START I/P FUSE BLOCK INDICATOR INSTRUMENT CLUSTER LT GRN WIRE MALFUNCTION INDICATOR LAMP (MIL) NCA WIRE OIL PRESS GAUGE ORG/ WIRE PNK PNK WIRE PNK WIRE RED WIRE SERVICE THROTTLE SOON INDICATOR SPEED METER TAN WIRE WAIT TO WATER IN FUEL INDICATOR WATER IN-FUEL INPUT WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

BLK WIRE BLU WIRE BRN (OR LT BLU) WIRE BRN WIRE BRN/WHT WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECM-BAT FUSE 6 ENG BAT FUSE 10 FUEL HEATER (PART OF FUEL/WATER SEPARATOR) FUEL LIFT PUMP (INSIDE RIGHT FRAME RAIL) FUEL PUMP PRIME CONNECTOR (TAPED TO FUEL PUMP RELAY BREAKOUT) FUEL PUMP RELAY (ON RIGHT SIDE OF DRIVER'S ISLAND) GAUGES FUSE 8 GRN WIRE GRY WIRE HOT AT ALL TIMES HOT IN RUN AND START I/P FUSE BLOCK INDICATOR INSTRUMENT CLUSTER LT BLU WIRE LT GRN WIRE MALFUNCTION INDICATOR LAMP (MIL) ORG/ WIRE PNK FEDERAL WIRE PNK PNK WIRE PNK WIRE RED WIRE SERVICE THROTTLE SOON INDICATOR SPEED METER TAN WIRE WAIT TO WASTEGATE SOLENOID (TOP LEFT REAR OF ENG) WATER IN FUEL INDICATOR WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

A/T A/T M/T BLK WIRE BLK/WHT WIRE BLU WIRE BRN (OR LT BLU) WIRE BRN WIRE BRN/WHT WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECM-BAT FUSE 6 ENG BAT FUSE 10 FUEL HEATER (PART OF FUEL/WATER SEPARATOR) FUEL LIFT PUMP (INSIDE RIGHT FRAME RAIL) FUEL PUMP PRIME CONNECTOR (TAPED TO FUEL PUMP RELAY BREAKOUT) FUEL PUMP RELAY (ON ENGINE FIREWALL RELAY BRACKET, UNDER BATTERY JUNCTION BLOCK) GAUGES FUSE 8 GRN WIRE GRY WIRE HOT AT ALL TIMES HOT IN RUN AND START I/P FUSE BLOCK INDICATOR INSTRUMENT CLUSTER LT BLU WIRE LT GRN WIRE M/T MALFUNCTION INDICATOR LAMP (MIL) ORG/ WIRE PNK FEDERAL WIRE PNK PNK WIRE PNK WIRE RED WIRE SERVICE THROTTLE SOON INDICATOR SPEED METER TAN WIRE WAIT TO WASTEGATE SOLENOID (TOP LEFT REAR OF ENG) WATER IN FUEL INDICATOR WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

A/C COMPRESSOR HIGH PRESSURE CUT-OFF SWITCH (ON REAR OF A/C COMPRESSOR) BLK WIRE BREAKOUT FOR CRUISE CONTROL MODULE, TOWARD RELAYS) BRN WIRE BRN/WHT WIRE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ENG BAT FUSE 10 ENGINE COOLANT TEMPERATURE SENSOR (ON TOP FRONT OF ENGINE) FUEL GAUGE FUEL PUMP MODULE (ON TOP OF FUEL TANK) GAUGES FUSE 8 GRY WIRE HOT AT ALL TIMES HOT IN RUN AND START I/P FUSE BLOCK IN PCM BREAKOUT, 20 CM FROM MAIN HARNESS TOWARD FUEL PUMP RELAY) INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE MALFUNCTION INDICATOR LAMP (MIL) "SERVICE ENGINE SOON" MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR (TOP CENTER FRONT OF ENGINE) MASS AIR FLOW SENSOR (RIGHT FRONT OF ENGINE COMP, ON AIR INTAKE ASSEMBLY) NCA WIRE ORG/ WIRE PNK 16 17 18 19 20 21 WIRE PNK 22 23 WIRE PNK PNK 2 3 WIRE PNK PNK WIRE PNK WIRE PPL PPL PNK 9 10 11 12 13 14 15 WIRE RED WIRE RED/BLK WIRE SPEED METER TACH THROTTLE POSITION SENSOR (ON THROTTLE BODY, TOP OF ENGINE) TRANS FUSE 17 WHT WIRE YEL WIRE

A/C COMPRESSOR HIGH PRESSURE CUT-OFF SWITCH (ON REAR OF A/C COMPRESSOR) BLK WIRE BREAKOUT FOR CRUISE CONTROL MODULE, TOWARD RELAYS) BRN WIRE BRN/WHT WIRE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ENG BAT FUSE 10 ENGINE COOLANT TEMPERATURE SENSOR (ON TOP FRONT OF ENGINE) FUEL GAUGE FUEL PUMP AND FUEL TANK SENDER (ON TOP OF FUEL TANK) FUEL PUMP/ OIL PRESSURE SWITCH (ON TOP LEFT REAR OF ENGINE) GAUGES FUSE 8 GRY WIRE HOT AT ALL TIMES HOT IN RUN AND START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE MALFUNCTION INDICATOR LAMP (MIL) "SERVICE ENGINE SOON" MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR (TOP CENTER FRONT OF ENGINE) MASS AIR FLOW SENSOR (RIGHT FRONT OF ENGINE COMP, ON AIR INTAKE ASSEMBLY) NCA WIRE OIL PRESS GAUGE ORG/ WIRE PNK 22 23 WIRE PNK PNK 2 3 WIRE PNK PNK WIRE PNK WIRE PPL PPL PNK 9 10 11 12 13 14 15 WIRE RED WIRE RED/BLK WIRE SPEED METER TACH TAN WIRE THROTTLE POSITION SENSOR (ON THROTTLE BODY, TOP OF ENGINE) TRANS FUSE 17 WHT WIRE YEL WIRE

BATTERY JUNCTION BLOCK (ON FORWARD LEFT SIDE OF BULKHEAD) BLK WIRE BLK/RED WIRE BRN WIRE BRN/WHT WIRE BYPASS DIST. REF HI DIST. REF LO DISTRIBUTOR DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ECM 1 FUSE FUEL GAUGE FUEL PUMP PRIME CONNECTOR FUEL PUMP RELAY (AT RELAY CENTER RIGHT SIDE OF MAIN SUPPORT AT DRIVER'S ISLAND) FUEL PUMP, SENDER (ON TOP OF FUEL TANK) FUSIBLE LINK (16 GA- GAUGES FUSE GRY WIRE HIGH VOLTAGE IGNITION COIL WIRE HOT AT ALL TIMES HOT IN RUN, START (CRANK) I/P FUSE BLOCK (MOUNTED ON THE I/P) IGNITION COIL (ON BRACKET AT REAR OF INTAKE PLENUM) IGNITION MODULE IGNITION SWITCH INSTRUMENT CLUSTER LOCK OFF OIL PRESS GAUGE ORG/ WIRE PICKUP COIL PNK 9 10 11 12 13 14 15 16 WIRE PNK PNK 1 2 3 4 5 WIRE PNK WIRE PPL PPL/WHT WIRE RED WIRE RUN WIRE SERVICE ENGINE SOON INDICATOR SPEED METER TACHOMETER TEST LEAD TAN WIRE TAN/BLK WIRE THROTTLE BODY FUEL INJECTOR NO.1 (ON TOP OF INTAKE MANIFOLD) THROTTLE BODY FUEL INJECTOR NO.2 (ON TOP OF INTAKE MANIFOLD) WHT WIRE